The objectives of this project are two-fold: (1) to elucidate the cellular mechanism(s) of secretory granule maturation in salivary acinar cells, and (2) to elucidate the structure and function of those macromolecular components of saliva which are characterized by high content of proline (proline-rich) or are responsible for non-immunoglobulin, saliva-mediated bacterial aggregation. The specific aims in studying the cellular mechanisms are directed toward purifying, characterizing and quantitating the sulfated macromolecules which are thought to be involved in secretory granule maturation, studying the interactions of these sulfated species with the other components of secretory granule contents, and determining the amount of condensation which is effected during secretory granule maturation. The specific aims concerning the structure and function of macromolecular components of saliva include determining the structural relationships of the various proline-rich proteins, their possible function(s) vis-a-vis changing the physico-chemical properties of other salivary components, and investigating the nature of the non-immunoglobulin bacterial agglutinins of saliva. The rat parotid will be used as an experimental model for the studies on secretory granule formation and human parotid saliva will be used as the source of proline-rich proteins and agglutinins. The studies on secretory granule formation should provide an understanding of how the secretory products are packaged and condensed in the salivary gland cells, a stage of the secretory cycle still poorly elucidated in exocrine cells and which could be critical to normal secretory ability. The studies on human parotid proteins and glycoproteins should lead to a more complete comprehension of the functions of saliva, the mechanisms whereby these functions are performed, and insights into the bases for abnormal oral conditions as they related to salivation.